Laundry detergent manufactures continually seek to improve the performance of their solid products, whilst at the same time improve their environmental profile. Catalysts, such as enzymes and/or bleach catalysts have been used to improve the performance of the detergent product
In addition, recent trends in improving the environmental and sustainability profile of the laundering process have reduced the amount of water being used during the laundering process. For example, consumer demand is increasing for automatic washing machines that use less water, use less rinsing steps, and have improved environmental profiles.
Catalytic laundry detergent compositions are known, such as WO2004/074419, which alleges that enzymes can be used to partly or fully replace detergent components such as surfactants, builders, polymers and bleaches and still provide superior cleaning. It is also of course common general knowledge that catalysts lower the activation energy of the reactions they catalyse. However, there is very little understanding about the activation energy reduction achieved by catalysts in a laundry detergent context, and there is little understanding or appreciation about how one must control the catalytic capability of a laundry detergent composition relative to other ingredients present in the detergent matrix.
Turning back to the trends of lower water usage during the laundering process, it becomes even more critical that the catalytic capability of a solid laundry detergent composition is understood and controlled. For example, smaller wash liquors mean higher concentration of active laundry detergent ingredients in the wash, which in turn means increased competition for fabric surface deposition. In addition, less water during the rinsing steps, and fewer rinsing steps, places greater stress on rinsing these laundry detergent ingredients from the fabric during the rinsing stage of the laundering process.
The inventors have found that controlling the catalytic capability of the solid laundry detergent composition relative to the electrolytic strength of the laundry detergent composition leads to improved fabric surface deposition of the catalysts, and an improved rinsing profile of the laundry detergent composition.
The inventors have found that reducing the electrolytic strength of the solid laundry detergent composition relative to the increasing its catalytic capability provides a solid laundry detergent composition having improved cleaning performance and improved rinsing profile.